A cam follower of this type will be gathered from JP 07063013 A, considered to be genre-defining, and has, as compared with cam followers, the follower bodies of which over their entire length possess a U-shape open toward the gas exchange valve, several advantages which are critical for the valve drive function. These include, on the one hand, the rigidity of the follower body, which is crucial for the valve drive dynamics and which, in the case of the trough shape, because of the then clearly higher surface moment of inertia, can be increased considerably with a correspondingly lower flexion of the cam follower. On the other hand, on account of this comparatively high surface moment of inertia, there is the possibility of reducing the wall thickness of the follower body to the benefit of a reduced mass moment of inertia and correspondingly lower inertia, contact and friction forces, with the rigidity of the follower body being sufficient as before.
A further advantage of the joint-side cross-sectional profile with a trough shape is the geometric design of the joint socket which at least for the most part runs within the longitudinal extent of the trough and which can surround with a markedly greater overlap angle a joint head arranged stationarily in the internal combustion engine and pivotably moveably supporting the cam follower. This increases the reliability of the cam follower against jumping off from the joint head, such as may occur, for example, in the case of contact losses in the valve drive as a result of excess rotational speeds of the internal combustion engine with correspondingly uncontrolled force angles between the joint socket and the joint head.
However, a substantial disadvantage of the cam follower proposed in the publication mentioned is founded on the practicability of forming the trough shape. This is such there that the sidewalls first ascending in the direction remote from the gas exchange valve merge, bent by 180°, into the second bottom portion which itself has a rectangular U-shape closed toward the gas exchange valve and having legs bearing directly against the sidewalls. However, the production of this trough shape entails an unusually high degree of forming of the follower body cold-formed from sheet metal material, so that, particularly in the transitional region between the U-shape and the following trough shape, from which the second intermediate bottom as it were penetrates between the sidewalls, material cracks in the follower body, and consequently a high reject rate during its production, must be expected. Furthermore, on account of the high notch effect of such a trough shape, there is also the risk of an insufficient fatigue fracture strength of the follower body, the premature fatigue fracture of which leads, as a rule, to considerable damage to the internal combustion engine.